- Colorful Combinations
- Artemisia Care Must-Knows
- Other Uses
- More Varieties of Artemisia
- Plant Artemisia With:
- Garden Plans For Artemisia
- The Genus Artemisia
- Species to Grow
- ‘Powis Castle’ Artemisia
- ‘Silver Mound’ Artemisia
- Sweet Wormwood
- Lovely in the Landscape
- Planting and Growing Artemisia
- Taking Care of Artemisia
- Propagating Artemisia
- Popular Varieties of Artemisia Grown in the UK
- Wormwood Powis CastleBotanical Name:Artemisia ‘Powis Castle’
- Artemisia ‘Powis Castle’
- How to Prune Artemisia Powis Castle
- Annual hard pruning
- Spring or early summer pruning
- Pruning an Artemisia
Grown primarily for its silver foliage, artemisia is a wonderful accent plant in many settings. Artemisias come in numerous different foliage shapes, sizes, and heights. A few well-known artemisias are ‘Silver Mound’ and the herb tarragon. Use these plants to add texture and subtle color to gardens, containers, and borders. Artemesias are also extremely versatile and drought tolerant.
With their beautiful silver foliage, artemesias are not “colorful” in the most basic sense. They do, however, work wonderfully as an accent to many other flowers and ornamental plants. The soft silver foliage plays very well with blues and purples, and it acts as a beautiful foil for hot colors to play off of as well. The plants are visually appealing, and many varieties like ‘Silver Mound’ are also a joy to touch with their exceptionally soft foliage. The flowers of artemisias are often fairly insignificant—usually small, almost petal-less blooms in soft yellow colors. Many gardeners prefer to remove these blooms, as the stalks can take away from the overall effect of the plant.
See tips on using silver in the garden.
Artemisia Care Must-Knows
The most important thing to know about artemisias is that these plants need well-drained soils. They can actually perform well in rock gardens too, growing in extremely sharp drainage with long droughts. Planting them in heavy soils, like moist clays, will most likely cause them to die out from rot. If they are grown in too moist of soil, the plants tend to grow very quickly and flop and fall open. Planting them in dry soils is an easy way to prevent this and keep plants more restrained.
See more perennials for the midwest.
Artemisias are plants that love sun and dry heat, so give them as much as you can. In part shade, plants are at much higher risk for disease and flopping issues. In areas with humid summers, many species of artemisia can be prone to foliar diseases and overall decline of the foliage—keep them in well-ventilated areas and full sun to prevent this. A hard cutback of the plants in summer can be beneficial to encourage new growth of previously suffering plants.
It is also important to note that many species of artemisia spread vigorously by rhizomes, or underground stems. Several types are actually considered invasive and should be watched when planted. If you have doubts about planting these, look for varieties that are slower to spread, or for mounding types that do not spread at all. You can also keep them in check by planting them in containers or regularly reining them in by digging up runners.
You may also know artemisia by one of its common names, wormwood. Many species of artemisia are prized for the various chemical compounds they produce, giving them a distinctive scent when crushed. One species in particular, Artemisia absinthium, is what gave the liquor absinthe its trademark ability to cause hallucinations. Today, this has been removed from absinthe recipes due to potential health hazards. Other types are used for medicinal properties, as well as tarragon in culinary uses.
More Varieties of Artemisia
Artemisia californica ‘Canyon Gray’ is a fantastic groundcover. Coastal sagebrush remains under 2 feet tall and forms a 10-foot-wide mat of fine textured silver-gray foliage. Zones 9-10
Artemisia vulgaris has a sagelike scent with mint undertones. Its primary use is in aromatherapy. Mugwort grows 2-4 feet tall and wide. The plant flowers from mid to late summer with greenish-white blooms. Zones 5-10
‘Powis Castle’ artemisia
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Artemisia ‘Powis Castle’ is a hybrid form that grows upright to 2-3 feet tall. Its finely divided foliage stays put, making it a welcome addition to the border and container plantings. Zones 7-9
‘Silver King’ artemisia
Artemisia ludoviciana ‘Silver King’ is a fast-spreading variety with bright silvery-white leaves that often turn reddish in autumn. Plant it on a slope in poor soil to prevent erosion. It grows 4 feet tall and is hardy in Zones 4-9.
‘Silver Brocade’ artemisia
Artemisia stelleriana ‘Silver Brocade’ (also called A. stelleriana ‘Boughton Silver’) grows only 6-8 inches tall and spreads a foot or more wide. Its lobed woolly white leaves are ideal to soften the edge of a container or retaining wall. Zones 3-7
Artemisia versicolor ‘Seafoam’ has frothy, contorted silver foliage that works well as a groundcover around taller, drought-tolerant perennials. It grows 8 inches tall and is hardy in Zones 4-10.
Image zoom French tarragon
Artemisia dracunculus, most commonly known as tarragon, is grown primarily for its use as a culinary herb and not for any ornamental qualities. Zones 5-9
Artemisia abrotanum, or southernwood, has feathery gray-green foliage with a lemony fragrance. The leafy stems work well to make wreath bases or moth-chasing sachets for closets and dresser drawers. Deer and rabbits leave it alone. Southernwood grows 3-5 feet tall and 2 feet wide. Zones 4-10
‘Silver Mound’ artemisia
Artemisia schmidtiana ‘Silver Mound’ forms a low mound of soft, fine-textured foliage to 1 foot tall that does not spread. Cut it back after its spring flush of growth to prevent the plant from flopping open midsummer. Zones 5-8
‘Valerie Finnis’ artemisia
Artemisia ludoviciana ‘Valerie Finnis’ offers lance-shape silvery leaves on an upright plant that grows 2 feet tall. Zones 4-9
Plant Artemisia With:
With its tall wispy wands of lavender or blue flowers and silvery foliage, Russian sage is an important player in summer and fall gardens. It shows off well against most flowers and provides an elegant look to flower borders. The aromatic leaves are oblong and deeply cut along the edges. Foot-long panicles of flowers bloom for many weeks. Excellent drainage and full sun are ideal, although very light shade is tolerated. Plant close to avoid staking since the tall plants tend to flop.
Few gardens don’t have at least one salvia growing in them. Whether you have sun or shade, a dry garden or lots of rainfall, there’s an annual salvia that you’ll find indispensable. All attract hummingbirds, especially the red ones, and are great picks for hot, dry sites where you want tons of color all season. Most salvias don’t like cool weather, so plant them outdoors after all danger of frost has passed.
Easy and undemanding, veronicas catch the eye in sunny gardens over many months. Some have mats with loose clusters of saucer-shape flowers, while others group their star or tubular flowers into erect tight spikes. A few veronicas bring elusive blue to the garden, but more often the flowers are purplish or violet blue, rosy pink, or white. Provide full sun and average well-drained soil. Regular deadheading extends bloom time.
Garden Plans For Artemisia
Artemisia is the genus name for a group of 200 to 400 different species. It is composed of hardy herbaceous plants and shrubs.
The Genus Artemisia
Some artemisia are considered a deadly poison, while tarragon, is used as a culinary herb. Except for tarragon, they should not be grown near food plants because of their toxicity, although some of them are used medicinally. Other general characteristics of the genus include:
- All artemisia species are bitter and have strong essential oils in them.
- Artemisia grows in the temperate areas of both hemispheres, usually in hot, semiarid areas.
- Most have hairy leaves and beautiful silvery green foliage. They are generally grown for this foliage, which overpowers the small flowers.
Common names for some popular species include mugwort, wormwood, sagebrush, and tarragon.
Species to Grow
Mugwort (Artemisia vulgaris) is also called a number of other names, including common woodworm, felon herb, chrysanthemum weed, wild wormwood, old Uncle Henry, sailor’s tobacco, naughty man, old man or St. John’s plant (not the same as St. John’s wort). Many related plants are referred to as mugwort by people, but Artemisia vulgaris is most often meant when a plant is called mugwort.
It is hardy to USDA zones 3-9. Mugwort is native to Europe, Asia, northern Africa and Alaska, and now grows wild in North America, where it is considered an invasive weed. The plant is silver grey, is bare on the upper side of its leaves and has hairs on the lower side of its leaves, and has small yellow flowers from July to September.
Mugwort is a herbaceous perennial with a woody root. It grows three to six feet tall. It reproduces by means of rhizomes. The seeds produced in temperate areas are rarely viable.
Mugwort is tolerant of most soils but prefers sandy, open areas and lime-rich soil. It grows well in slightly acidic to slightly alkaline soils. Mugwort prefers well drained areas and likes dry soil. It should only be watered during extreme drought. It grows best in full sun but can tolerate dappled shade.
To grow mugwort, purchase a plant or break off a piece of rhizome from an existing plant and plant it. Mugwort should be planted after all danger of frost has passed. Seeds are ready to harvest in autumn. Leaves are harvested when needed.
Uses of Mugwort
Mugwort is supposedly so named because it was used to flavor mugs of beer brewed by individuals for their own use. It went out of favor for this purpose when hops came into favor. It can cause dermatitis on contact to some individuals, should never be taken in quantities of greater than one ounce at a time or many days in a row, and should be avoided by pregnant women, who it may cause to miscarry. According to WebMD, it can be quite dangerous to use.
Flowers or seed heads may be steeped into a tea. Leaves are used in small quantities as a digestive aid, especially in fatty foods. The Japanese use the young shoots as a potherb. Mugwort is often grown in gardens as an herbal insect repellent. Mugwort is also used in homeopathic medicine to treat epilepsy.
‘Powis Castle’ Artemisia
‘Powis Castle’ artemisia is an evergreen perennial. It can also be classified as a shrub or sub-shrub. ‘Powis Castle’ is believed to be a cross between Artemisia arborescens and Artemisia absinthium. This plant is a beautiful silver grey plant that grows up to three feet tall and three to six feet in diameter. The leaves are like filigreed silver lacework. ‘Powis Castle’ rarely flowers, but occasionally produces six-inch panicles of silver, yellow-tinged flower heads.
Growing ‘Powis Castle’ Artemisia
‘Powis Castle’ grows in zones 6 to 8. It does not take heat in the summer well or cold in the winter well. It is propagated by cutting shoots in the summer and rooting them. Any seeds it produces will not produce a plant like its parent. ‘Powis Castle’ grows in full sun and prefers neutral to mildly alkaline, well-drained soil. It is drought tolerant but will rot in wet soil. It should be pruned in the spring when it first starts growing to keep it in a mound shape.
Uses of ‘Powis Castle’ Artemisia
‘Powis Castle’ is used as an edging, in xeriscape gardens, cottage garden, rock garden, and in herb gardens. It is toxic and should not be consumed. ‘Powis Castle’ is planted for its dramatic foliage, not its flowers.
‘Silver Mound’ Artemisia
‘Silver Mound’ (Artemisia schmidtiana) is prized for its silver foliage and attractive mounding growth. It is a perennial with a low, spreading habit. It is more heat tolerant than most artemisia plants and is not invasive. It lives in zones 4-8. ‘Silver Mound’ grows ten to twelve inches tall and rarely flowers. It is deer resistant and rabbit resistant. ‘Silver Mound’ is attractive to bees, butterflies, and birds.
Growing ‘Silver Mound’ Artemisia
‘Silver Mound’ grows in full sun. It likes dry soil and should be watered rarely after it is established. It is generally purchased as a plant, rather than propagated. However, it can be propagated by cutting shoots in summer and rooting them. ‘Silver Mound’ likes average soil. Very fertile soil makes it grow too fast, requiring division every year. Normally, it should be divided every two to three years.
After planting ‘Silver Mound’, it rarely requires much in the way of maintenance. Trimming it in the spring will keep it in a nice mound shape. Do not trim old wood, trim back to a new bud. The trimmings can be rooted to start new plants. The plant can be sheared during the summer to create fresh foliage if needed.
Use of ‘Silver Mound’ Artemisia
‘Silver Mound’ is used as edging or an accent piece because of its spectacular foliage. It is perfect for a border or a meandering path. Because it is drought tolerant, it does well in a rock garden or other xeriscape.
Sweet wormwood (Artemisia annua) is also known as sweet annie, sweet sagewort, annual mugwort or annual wormwood. It is an annual herbaceous plant that has been used medicinally for centuries. It is from Asia but is widely naturalized around the world. Sweet wormwood grows to be nine feet tall and three feet wide and grows rapidly.
Growing Sweet Wormwood
Sweet wormwood is cultivated from seeds. These are sown after all danger of frost has occurred. The seeds are tiny and should be sown three feet apart in rows separated by three feet. Sweet wormwood can also be propagated by cuttings from another plant. This is done with spring shoots and is very labor intensive. Most people buy a sweet wormwood plant from the nursery. It needs direct sun and average soil. It does need well drained soil as it will not tolerate wet feet. It is drought tolerant.
Use of Sweet Wormwood
Sweet wormwood contains a compound named artemisinin, which is the leading treatment for malaria in the world. Sweet wormwood is rarely grown for anything but access to this compound. The leaves are harvested, and a solvent is used to leach the compound from the leaves.
Tarragon (Artemisia dracunculus) is a culinary herb that is native to a wide area of the Northern Hemisphere. The best culinary herb is called French tarragon, to distinguish it from Russian tarragon, another cultivar, or wild tarragon, which isn’t as flavorful as French tarragon. Tarragon grows in zones 5 to 8. It grows up to three feet tall and spreads up to two feet. French tarragon rarely flowers and its seeds are generally sterile.
Tarragon is usually purchased at the nursery. The seeds of the best tasting tarragon are usually sterile so it is propagated by root division. Tarragon should be planted after all danger of frost has passed. Tarragon likes moderate sun with a little shade in the afternoon. It prefers rich, loamy soil with good drainage. Adding compost to your soil is a good way to prepare it for tarragon. It is divided in the fall and replanted about 18 inches apart. It has a shallow root system and care must be taken during weeding not to damage the roots.
Use of Tarragon
Tarragon is used as a culinary herb to flavor soups and other dishes. It is harvested in summer and the leaves are dried for use later. The young shoots can be cooked as a potherb. Tarragon is thought to aid digestion and is often used to flavor oily foods.
Wormwood (Artemisia absinthium) is a woody perennial that has beautiful silvery gray foliage. That is the primary reason it is planted. All parts of the plant should be considered poisonous. Wormwood is from the temperate regions of Europe and Asia and has naturalized in parts of the United States. It is considered invasive in some areas.
Wormwood grows to three feet high by three feet wide. Wormwood is purchased from a nursery and is best grown in poor to moderate soils that are dry to moderately moist. It suffers from root rot in wet soils. It is drought resistant and rarely needs watering once established. It needs full sun to do best.
Wormwood is propagated by dividing the root ball and planting the new divisions 18 inches apart. It can also be propagated from stem cuttings. Cut it down to its base in the winter.
Use of Wormwood
Wormwood is grown for its dramatic silver grey foliage. It makes a good border or accent piece. It is also grown to obtain plants to produce absinthe, a spirit that for many years was outlawed in the United States. It is again legal and is distilled from the whole plant. It was outlawed because it was thought to be addictive and psychedelic, but that has not proven to be the case upon further study, or at least no more than any other alcohol.
Lovely in the Landscape
Artemisia is characterized for its beautiful silver grey foliage and is generally grown for that reason. In general, it makes a nice border or accent piece, is drought resistant, and is deer and rabbit resistant.
A group of perennials, herbs and shrubs, grown mainly for their attractive and decorative foliage (the flowers are often tiny and insignificant). They make a good foil for other flowering plants and most forms are useful in flower arrangements.
Family: Asteraceae (daisy)
Botanical Name: Artemisia
Common Names: Wormwood, old man, old woman, lad’s love, dusty miller, mugwort
Foliage: Evergreen or deciduous. Finely textured and often aromatic. Usually in tones of white, silver and grey but variegated forms are also available.
Flowers: Clusters of tiny insignificant white or yellow flowers.
Flowering Period: Summer (July-September)
Soil: Any light, well-drained, reasonably fertile soil. Chalk, sand or loam. Drought tolerant. Avoid heavy, poorly-drained soils.
Conditions: Best in full sun.
Type: Herbaceous perennial or hardy shrub.
Origin: Asia, Canada, Americas and Europe.
Hardiness: Hardy in most areas of the UK.
Planting and Growing Artemisia
Plant in an open sunny location. Dwarf forms make excellent rock garden plants. Silver leaf forms are perfect for a silver and white colour scheme. This plant’s drought tolerance makes it a good choice for low maintenance gardens.
Taking Care of Artemisia
Remove faded flowers from shrubs.
Cut back herbaceous perennials to ground level in October. Remove any leggy stems from shrubs.
Pests and Diseases
Large leaf perennials are susceptible to attack by aphids. May also be affected by rust disease.
Divided established perennials when the plants are dormant, between October and April.
Propagate shrubs by taking 3-4in (7.5-10cm) long heel cuttings in later summer and root in a light sandy compost, in a cold frame.
Popular Varieties of Artemisia Grown in the UK
A. absinthium (common wormwood) a sub-shrub, with silver feathery foliage and yellow flowers in early summer. ‘Lambrook Silver’ is a good variety. Height and spread 3ft (90cm).
A. lactiflora (white mugwort) a tall perennial form with lobed green leaves. Plumes of creamy-white flowers appear in late summer. Height 4 to 5ft (1.2-1.5m), spread 1.5ft (45cm). Excellent for fresh and dried flower arrangements.
A. stelleriana (dusty miller, old woman) a tall perennial with silver, deeply lobed leaves. Clusters of yellow flowers appear in late summer. Height 1.5 to 2ft (45-60cm), spread 1ft 30cm).
A. schmidtiana ‘Nana’ is a low growing form with aromatic evergreen silver filigree foliage. Tiny yellow flowers appear at the tips of the foliage in early to late Summer. Height 4in (10cm), spread 12in (30cm).
Wormwood Powis Castle
Botanical Name:Artemisia ‘Powis Castle’
Wormwood ‘Powis Castle’ is an evergreen, woody perennial growing from 10 to 90 cm high and equally wide. There are reports of it growing quite large, however, it is likely that 45cm would be an expected height in many regions. It forms dense spreading clumps of silver grey leaves. The aromatic foliage is finely divided and feather like. The flowers are yellow, but insignificant, so they are often cut off simply to encourage the foliage display. However, the flowers are fragrant and appear from early autumn to late summer.
‘Powis Castle’ is said to be the best known Artemisia in the UK, where it is a firm favourite. The exact origins of this variety of wormwood are unknown, but it was found in a local garden and a cutting was taken by Jim Hancock in 1968. It is thought to be a cross between A. arborescens and A. absinthium. Hancock later became the Head Gardener at Powis Castle in the United Kingdom and introduced the wormwood hybrid to the gardens there. In 1972, the plant was given the name ‘Powis Castle’ by Jim Sales or Graham S Thomas, in order to help promote the National Trust Garden program.
Like many members of the Artemisia genus, ‘Powis Castle’ is grown largely for its ornamental and aromatic foliage. The silver grey foliage is ideal for contrast garden borders and is surprisingly ‘colourful’.
Wormwood ‘Powis Castle’ is a hardy plant and is evergreen in warm winter climates. It prefers soil of a dry to medium moisture level. It is an excellent plant to try in dry areas with poor to medium soil quality. The soil must be very well drained as high moisture levels will cause root rot.
If planted in full sun ‘Powis Castle’ does well, but some shade can be tolerated. If grown in too much shade the plant may become limp and lose overall quality in the leaf structure. Plant quality may also decline in areas of high humidity.
To propagate cuttings can be taken from side shoots in summer. However, it is perhaps more useful to divide a clump and replant. After a few years clumps may need to be divided to improve vigour and quality, or to remove unwanted plants. Although this plant spreads by creeping rhizomes, it is not considered invasive.
Powis Castle may be pruned to keep its shape in spring, when still growing. Leave enough buds to ensure that growth continues and that a bushy habit develops. Do not prune to the ground or prune in autumn when there is no active growth occurring. Generally this plant is considered low maintenance.
A Note on the Wormwoods
Wormwood is the common name for many plants in the Artemisia genus, which has from 200-400 named species. Each species quite likely also has many synonyms. In many cases, the name wormwood is used interchangeably with mugwort, although they are two separate species. When looking for a specific plant, be sure to check for the scientific name so you can have some certainty.
The wormwoods are hardy, woody perennials that remain evergreen during warm winters. In colder regions they generally return in spring when the seasons change. Most are very hardy, having originated in arid or semi-arid regions with poor soils and limited moisture. Some of the plants in this genus do have greenish foliage, but many have silver – grey – white foliage and these are highly prized ornamental plants. They usually have insignificant flowers and many hybrids do not produce viable seed. Most are best propagated by cuttings.
The name Artemisia is from Ancient Greek used in Hellenistic cultures, where the Goddess Artemis was the goddess of the hunt, protector of the forest and children. Artemis was also a protector of women, particularly those experiencing childbirth. The goddess Artemis was also said to be the goddess of the herbalist. The term wormwood is from the Middle English wormwode or wermode, which was attributed to the plants antihelminthic attributes in helping to expel worms from the body.
Plants such as wormwood, mugwort and sagebrush are all known for their high essential oil content. All are well known, with a long tradition in magic and folklore, where they are used for both their natural and supernatural properties. In old times, hanging Artemisia on the door was a sign that a midwife or herbalist was in residence.
Artemisia ‘Powis Castle’
Used widely in gardens for the silvery gray foliage, Artemisia Powis Castle does require regular pruning to keep its attractive foliage in good shape.
Without proper pruning it can become a little leggy and loose that attractive mounding habit that we want in the garden.
Pruning is important from first planting, as this forms the structure of the plant for future growth. If left, you can see that growth can become sparse, with dormant buds lower down.
How to Prune Artemisia Powis Castle
Two types of pruning can be used, the annual hard prune, and the spring to summer tidy up
Annual hard pruning
The best time to prune is in early spring as the buds begin to push out, but before new foliage appears. You can cut back ‘almost’ to the ground. The trick is to look for active buds.
You can do this with some sharp Secateurs. Look on the stems for growth buds and cut back to these, aim for around 5cm (2 inches) for the ground in young plants. As plants get older and woodier you will need to prune higher up.
If you are unsure how hard you can prune, just look for the best buds you can see and prune back to them. In spring more buds will push out lower down and you can them do a secondary pruning to them. You can easily see the buds on growth that is 1 -2 years old in the picture right. If you can leave 2 or 3 of these on a stem you are well on the way to successful pruning.
Cutting back into old wood with no buds evident can either be successful, or it can kill the plant.
Spring or early summer pruning
Once the plant begins to show good growth you can give it a bit of a chop to make the growth even bushier. Try a 1/3 prune back into foliage at this time. This is also a good time to give the plant some fertilizer.
You may also be interested in
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- Pruning Artemisia Powis Castle
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Pruning an Artemisia
Pruning your Artemisia shrubs will allow for healthier growth, more foliage and flowers and overall better looking plants. Many people are reluctant to prune their shrubs for fear of causing irreparable damage to the plant. However, neglecting to prune your Artemisia can prove to be even more damaging to them. Here is a guide to help you properly prune your artemisia plants.
Step One – Know When to Prune
Artemisia plans should be pruned or cutback in early spring. This will provide the best chance for new growth and more blooms during warmer weather.
Step Two – Cut Away Dead Growth
Start your artemisia pruning by cutting away the dead growth or damaged branches with your pruning shears. You can also use loppers or a saw to do this as well. Whatever you use, make sure the tool is sharp to avoid causing too much stress to the plant.
Step 3 – Artemisia Pruning Cuts
When pruning your Artemisia plants, make angle cuts at about 45 degrees. Make your angled cuts away from the direction of the buds and branch growth. For older and more mature artemisia plants, make cuts of about 6 inches. For younger artemisia plants, cut only about three or 4 inches off the end of the branches.
Step 4 – Don’t Prune Too Much
Make sure not to cut away too much in one pruning. While an older and more mature Artemisia plant may be able to withstand severe pruning, younger artemisia plants will almost certainly die if too much growth is removed at once.
Step 5 – Try Not to Cut New Growth
Always avoid cutting away new growth from your artemisia plants. Generally speaking, it will be fairly easy to identify new growth from older and less healthy growth. Growth from newer branches will generally be lighter in color and will appear healthier and more robust overall. Try to cut away the old growth and allow newer branches to fill in the spaces created by your pruning.
Step 6 – Maintenance Pruning
While extensive planning for your artemisia plants should be done in the early spring, you can do maintenance pruning to remove dead growth and branches at any time during the year. Fall, winter, and summer pruning can be very effective. Removing dead growth and branches from your artemisia plants about three or four times a year is usually a very good idea and will allow for healthier growth and encourage flowering in the spring and summer.
Step 7 – Shaping Considerations
When pruning your artemisia plants, you should be consistent and not attempt to drastically change the shape of your artemisia plants. Once you choose a shaping style, stick to your design, otherwise you may have to cut away too much new growth. If you want to change the way your artemisia plants are shaped, you should wait until you divide them in the spring and wait for the new shrubs to grow.